The present invention relates to a material pusher, and more particularly to a feeding section of the material pusher.
Referring to FIG. 1, a single-shafted material pusher of prior art is shown comprising a long tubular cylinder 11, a threaded rod 12 disposed pivotally in the cylinder 11, a driving device 13 for use in driving the threaded rod 12 to rotate, a feeding funnel 14 attached to a portion of the cylinder 11 adjacent to the driving device 13, and a heater for heating the cylinder 11. The granulated plastic material is fed into the cylinder 11 via the funnel 14 and is subsequently carried forward by the rotating threaded rod 12. In the meantime, the plastic material is subjected to melting caused by the heat generated by the heater 15, while it is being carried forward by the threaded rod 12. The molten plastic material is finally pushed out via a free end of the cylinder 11.
The rate of processing the granulated plastic material in the cylinder 11, as described above, is dependent to a great extend on the thread interval of the threaded rod 12. It is quite impractical to have the thread interval of the threaded rod 12 shortened with a view to accelerating the rate of processing the granulated plastic material. Therefore, the only workable option is to increase the rate of rotation of the threaded rod 12 and the heat generated by the heater 15. However, the threaded rod 12 should not be subjected to an excessive acceleration because the moment required for the threaded rod 12 to rotate is considerably large in view of the facts that the threaded rod 12 is rather long and that the granulated plastic material fed into the cylinder 11 must be compressed before it is heated. IN some instances, the granulated plastic wastes are washed and dried before they are fed into the feeding funnel of the material pusher. Such operation often runs the risk of getting the feeding funnel obstructed by the granulated plastic wastes. A conventional solution to such problem is to install in the feeding funnel a spiral blade, which serves to feed the material forcefully. However, such band-aid approach to the problem provides no permanent answer to a serious problem as such, because it fails to enhance the compression ratio of the plastic material in the threaded rod so as to accelerate the feeding speed.